Bipolar - Lithium Flashcards
Lithium
Used for the prophylaxis and treatment of mania, hypomania, depression in bipolar disorders, resistant depression and aggressive or self-harming behaviour.
Therapeutic range
0.4 mmol/L - 1 mmol/L (lower end for prophylactic treatment/elderly)
0.8 mmol/L - 1 mmol/L for acute manic episodes, patients who have previously relapsed or have subsyndromal symptoms
Plasma lithium monitoring
Blood samples taken 12 hours after dose.
Weekly, then every 3 months once dose stable for the first year, then every 6 months thereafter.
Additional monitoring if:
- Significant intercurrent illness
- Significant changes to diet or water intake
Lithium - monitoring (other)
EVERY 6 MONTHS
- Renal function
- Cardiac function
- Thyroid function
Withdrawal
Avoid abrupt withdrawal
Higher risk of relapse otherwise
Toxicity
REVeNGe
Renal disturbances
Extrapyramidal symptoms
Visual disturbances (blurred vision)
Nervous system disturbances
GI effects (diarrhoea/vomiting)
Renal disturbances
Polyuria
Incontinence
Hypernatremia
Extrapyramidal symptoms
Fine treatment increasing to course tremor
Ataxia
Dysarthria
Myoclonus
Nystagmus
Muscle weakness
Nervous system disturbances
Confusion and drowsiness, increasing to incoordination, restlessnes and stupor
Other symptoms of lithium toxicity
Signs and symptoms of hypothyroidism
- Unexplained fatigue
- Weight gain
- Hair loss
Signs and symptoms of benign intracranial hypertension
- Persistent headache
- Visual disturbances
What levels is lithium toxic at?
2 mmol/L
Effects of toxicity
Seizures
Coma
Renal failure
Arrhythmias
BP changes
Circulatory failure
Death
Lithium - Side effects associated with long-term use
Mild cognitive/memory impairment
Thyroid disorders
- Monitoring = thyroid function tests
- Hypothyroidism = weight gain/fatigure
- May also cause hyperthyroidism
Lithium - other side effects
Renal impairment
- Lithium is nephrotoxic and renally cleared
- Monitoring = renal function tests
- Reporting = polyuria, polydipsia
Benign intracranial hypertension
- Reporting = persistent headaches, visual disturbances
QT prolongation
- Monitoring = cardiac function
Lowers seizure threshold
Lithium - Prescribing
Prescribe by brand.
Lithium salts and different preparations vary in bioavailability.
Lithium + hyponatraemia
Patients with hyponatraemia who take lithium are predisposed to lithium toxicity
Pregnancy + BF
Teratogenic
Effective contraception in women of child-bearing age.
Toxicity can occur in breastfed infants
Counselling points
- Report signs and symptoms of lithium toxicity
- Maintain constant, adequate salt + water intake. ESP if infection, diarrhoea or vomiting (can cause dehydration)
- Can cause drowsiness. Avoid alcohol. Don’t drive/operate skilled machinery if drowsy.
- Lithium treatment pack = PIL, alert card, record book. Always carry with you
Interactions - increases risk of seizures
Quinolones (ciprofloxacin)
SSRIs
Epilepsy (lowers seizure threshold)
Interactions - lithium toxicity
Reduced renal excretion = increased risk of toxicity
- ACEi/ARBs
- NSAIDs
Causes hyponatraemia which predisposes to lithium toxicity
- Diuretics
- Antidepressents
Interactions - increased risk of extrapyramidal symptoms
Antipsychotic drugs
- Haloperidol
- Clozapine
- Metoclopramide
Parkinson’s disease
Metoclopramide
Interactions - increased risk of neurotoxicity
Phenytoin
Carbamazepine
Antipsychotics
Amitriptyline
Interactions - Increased risk of serotonin syndrome
Sumatriptan (5-HT1a agonist)
Citalopram (SSRIs)
Granisetron
MAOIs
Amfetamines
St. Johns Wort
Tramadol
Interactions - QT interval prolongation = increased risk of arrhythmias
Drugs that prolong QT:
- Quinolones
- Citalopram
- Clarithromycin
- Amiodarone
- Antipsychotics
- Imipramine
Drugs that cause hypokalaemia (can lead to QT interval prolongation):
- Theophylline
- Corticosteroids
- B2 agonists
- Loop/thiazide diuretics
Interactions - OTC
Soluble/effervescent analgesics (high salt)
Sodium containing antacids
